The invention concerns a rotary valve for controlling the cylinder charge change of an internal combustion engine having a plurality of combustion chambers. Two fresh gas or exhaust gas ducts associated in each case with adjacent combustion chambers extend as regards their region in a cross-sectional zone of the rotary valve. The engine also contains a common fresh gas or exhaust gas opening in the rotary valve housing.
In the case of a cylindrical slide valve having a construction known from DE-OS No. 3,241,723, the exhaust gas ducts of the two combustion chambers (cylinders) which are adjacent in each case are arranged, with a view to limit the length of the rotary valve in the direction of its axis which coincides with its axis of rotation, in such a manner that their points of opening which face the common exhaust gas opening in communication with a conventional exhaust gas system are offset angularly over the periphery of the rotary valve, i.e., they are located in a common cross-sectional plane also containing the exhaust gas opening. The points of confluence which serve as a connection between the two exhaust gas ducts and the cylinder concerned, however, are offset on the rotary periphery both in the peripheral and in the axial directions, the axial offset being determined, among others, by the axial separation of the cylinders. The common cross-sectional region and, respectively, the common cross-sectional plane practically coincide with the plane of separation between the two adjacent cylinders.
In accordance with this state of the art, the exhaust gas ducts associated with adjacent cylinders are thus located next to each other as regards their placement in the aforementioned cross-sectional plane. While this offers advantages in that it results in a relatively short rotary valve, the course of the ducts in the cross-sectional plane next to one another necessitates a relatively large diameter of the cylindrical rotary valve in that otherwise, the duct regions arranged with angular offset within one cross-sectional region cannot be provided with sufficiently large flow cross sections.